When a wagon crashes into a ravine, prospector Ben Rumson finds two adult male occupants, brothers, one of whom is dead and the other of whom has a broken arm and leg. As the first man is about to be buried, gold dust is discovered at the grave site. Ben stakes a claim on the land and adopts the surviving brother as his "Pardner" while he recuperates.

Pardner is initially innocent and romantic, illustrated by him singing a pining love song about a girl named Elisa ("I Still See Elisa"), who he later sheepishly confesses exists only in his imagination. Pardner is a farmer who hopes to make enough in the gold rush to buy some land, and is openly suspicious of the drunken and seemingly amoral Ben. Ben claims that while he is willing to fight, steal, and cheat at cards, his system of ethics does not allow him to betray a partner. Ben will share the spoils of prospecting on the condition that Pardner takes care of him in his moments of drunkenness and melancholy.

After the discovery of gold, "No Name City" springs up as a tent city with the miners alternating between wild parties ("Hand Me Down That Can o' Beans") and bouts of melancholy ("They Call the Wind Maria"). The men become increasingly frustrated with the lack of female companionship, so the arrival of a Mormon, Jacob Woodling, with two wives is enough to catch the attention of the entire town. The miners claim it is unfair for the Mormon to have two wives when they have none. They persuade him to sell one of his wives to the highest bidder. Elizabeth, Jacob's younger and more rebellious wife, agrees to be sold based on the reasoning that whatever she gets, it can't be as bad as what she currently has.

A drunken Ben winds up with the highest bid for Elizabeth. Ben is readied for the wedding by the other miners ("Whoop-Ti-Ay"), and is married to Elizabeth under "mining law," with Ben being granted exclusive rights to "all her mineral resources." Elizabeth, not content to be passively treated as property, threatens to shoot Ben on their wedding night if she is not treated with respect. While she believes Ben is not the type to truly settle down, this is acceptable if he builds a proper wooden cabin to provide her with some security for when he inevitably leaves. Ben is impressed by Elizabeth's determination. He enlists the miners to keep this promise, and Elizabeth rejoices in having a proper home ("A Million Miles Away Behind the Door").

Sensing the other miners becoming obsessed with her, Ben is consumed by jealousy and paranoia. News comes of the pending arrival of "six French tarts" to a neighboring town and a plan is hatched to kidnap the women and bring them to "No Name City" ("There's a Coach Comin' In"), thus providing the other miners with female companionship. The town will prosper with additional sources of income as other miners from outlying regions will likely be willing to spend their money in No Name City if it means a chance to visit prostitutes. Ben heads up the mission and leaves Elizabeth in the care of Pardner. The two fall in love ("I Talk to the Trees"), whereupon Elizabeth, saying she also still loves Ben, convinces them that "if a Mormon man can have two wives, why can't a woman have two husbands?"

As the town booms, the arrangement with Ben, Pardner, and Elizabeth works well for a while. But soon the town becomes large enough that more civilized people from the East begin to settle there. A parson begins to make a determined effort to persuade the people of No Name City to give up their evil ways, warning the townsfolk that they will be swallowed up by God's wrath if they do not repent ("The Gospel of No Name City"). Meanwhile, a group of new settlers is rescued from the snow, and the strait-laced family is invited to spend the winter with Elizabeth and Pardner, who is assumed to be her only husband.

Ben is left to fend for himself in town. In revenge, he introduces one of the family, naive young Horton Fenty, to the pleasures of Rotten Luck Willie's saloon and cat house. This leads to Elizabeth dismissing both Ben and Pardner from the log cabin. Pardner takes to gambling in Willie's ("Gold Fever"). As the gold begins to play out, Ben and a group of miners discover that gold dust is dropping through the floor boards of many of the saloons. They tunnel under all the businesses to get at the gold ("The Best Things in Life Are Dirty"). This brings the story to its climax when, during a bull-and-bear fight, the streets collapse into the tunnels dug by Ben and the others and the town is destroyed. A reprise of "The Gospel of No Name City" plays as the town is literally swallowed by the earth.

It is time for Ben to move on to the next gold field ("Wand'rin' Star"). Elizabeth and Pardner reconcile and plan to stay. As Ben departs, he comments that he never knew Pardner's real name, which Pardner then reveals: Sylvester Newel.

Chayefsky provided a significantly changed storyline from the stage musical version. In the film "Rumson City" is simply called "No Name City," and Ben Rumson has no daughter. The character "Julio" is replaced by "Pardner", now an American and Ben's partner in the gold claim. Additionally, in the film it is Pardner who falls in love with Elizabeth, Ben's wife under mining law, rather than the stage musical character Edgar Crocker. The temporary solution to the love triangle among Ben, Pardner and Elizabeth appears only in the film as well. In the stage version, Ben Rumson dies at the end; in the film he survives.

Paint Your Wagon was shot near Baker City, Oregon with filming beginning in May 1968 and ending in October.[2] Other locations include Big Bear Lake, California and San Bernardino National Forest; the interiors were filmed at Paramount Studios with Joshua Logan directing. The film's initial budget was $10 million, before it eventually doubled to $20 million. A daily expense of $80,000 was incurred to transport cast and crew to the filming location, as the closest hotel was nearly 60 miles away. The elaborate camp used in the film cost $2.4 million to build.[2]

The film was released at a time when movie musicals were going out of fashion, especially with younger audiences. Its overblown budget and nearly 3-hour length became notorious in the press. Eastwood was frustrated by the long delays in the making of the film, later saying that the experience strengthened his resolve to become a director. According to Robert Osborne, Marvin drank heavily during the filming, which may have enhanced his screen appearance, but led to delays and many retakes.

Paint Your Wagon was released in United States theaters in October 1969. The film became Paramount's sixth largest success up to that point (and the sixth highest grossing film of 1969) when it earned $31.6 million over its release, although the earnings never offset the cost of production and marketing.[7]

Critical reception was mostly negative. Paint Your Wagon currently maintains a 21% "rotten" approval rating on Rotten Tomatoes, although it was more popular with audiences with a score of 69%.[8]

Marvin's deep-voiced rendition of "Wand'rin' Star," accompanied by the film's choir, became a hit in the UK.[9] His voice was described by Jean Seberg as "like rain gurgling down a rusty pipe". Interviewed on NPR, Marvin said that the song was a hit in Australia, and someone there described it as, "The first 331⁄3 recorded at 45."